This invention relates generally to infusion systems for the administration of medications and, more particularly, to a refillable and subcutaneously implantable infusion reservoir and pump system useful for pain management in the treatment of terminally ill patients.
It has been found in the treatment of many terminally ill patients that the administration of various medications over sustained periods of time is necessary. For instance, it is often desirable to provide a pain killer, such as morphine, to such patients to help them cope with the sometimes excruciating pain which accompanies certain diseases. Frequently, terminally ill patients experience such extreme pain that hospitalization becomes necessary to provide the patient medications at intervals and in quantities sufficient to meet the patient's needs. Alternatively, when hospitalization is not acceptable, the patient is often required to obtain private nursing care.
Requiring a terminally ill patient to either be hospitalized or to arrange for private nursing care can result in substantial burdens being imposed upon both the health care system and the patient. Health care facilities are increasingly burdened as the demand for hospital bed space increases at a rate greater than the growth in available bed space. This burden is accentuated when patients, such as terminally ill patients, are hospitalized for want of an alternative treatment methodology. Also, the diversion of medically trained personnel to deal with the routine infusion of medications to terminally ill patients imposes additional burdens on the health care system which could be avoided, provided the proper technology were available.
When patients must be confined to a hospital bed or arrange for private duty nursing care to receive prescribed medications, the costs involved often exceed the financial means of such patients. For example, many terminally ill patients cannot afford to pay for the very expensive and individualized care which could make the last period of time prior to death much more productive and less difficult for the patient and for those around him. Indeed, many such patients cannot afford any medical care whatsoever and their only available alternative is to forego available treatments. Sometimes patients who cannot afford the hospitalization or private nursing care required and who cannot tolerate the pain involved with a particular disease must be hospitalized at society's expense.
These burdens to the patient, the health care system and to society in general have prompted several changes in health care methodology. For instance, many physicians have found it desirable to administer prescribed medications on an out-patient basis. This out-patient technique has proven to be effective in substantially reducing the costs associated in the treatment of many types of ailments; however, there have been a number of drawbacks which have made such out-patient arrangements less than ideal.
A typical drawback of out-patient treatment programs includes the requirement of frequent visits by the patient with the physician and the resultant time and transportation problems. It is generally recognized that if the patient could be provided adequate home care for extended periods of time, the time between visits with the physician could be lengthened. Such extended home care would benefit the physician, as well as the patient, in many circumstances by permitting the physician to devote more professional time to other important matters.
Notwithstanding the foregoing, some patients find that receiving regular injections of medications over a prolonged period of time is distasteful, not to mention painful. Additionally, it has been found that repeated injections through the skin into a specific, limited area of the body can be harmful to the patient and can sometimes cause problems which could become more threatening to the well-being of the patient than the illness being treated. Such problems have made necessary the use of alternate injection sites, the rotation of injections among alternate injection sites, or, at the extreme, the abandonment of medication injections as a useful form of treatment.
Moreover, some substances have been found to traumatize the skin when injected, and this has necessitated the use of alternate means for introducing such substances into the body. Such alternate introduction means have included the use of catheters which are inserted through the skin into the body and have a portion which remains extended through the patient's skin to provide external access. This and similar infusion systems have proven to be undesirable for extended treatment because of the risk of infection at the incision site where the catheter extends through the skin.
Accordingly, there has been a need in the medical arts for a system, including the appropriate devices, which allows the patient or his loved ones to administer required medications in precise quantities while minimizing the number of injections required and visits which need be made with a physician. Such a system should be constructed for total subcutaneous explacement in the body, include appropriate devices to prevent the unintended infusion of the medications into the body, and be refillable, such as by injection, to permit long term use. The present invention fulfills these needs and provides other related advantages.